The invention relates generally to medical devices and more particularly to an electrode kit for use in functional electrical stimulation treatment in conjunction with an orthosis.
An orthosis, such as a splint, cuff or garment, can be used in conjunction with an electrode to provide electrical stimulation of, for example, paralyzed limbs in therapeutic exercises and for generating limb function during functional electrical stimulation (FES). An electrode kit for such use can include, for example, a base portion that can be attached to an interior surface of an orthosis and an electrode assembly including an electrode and a pad that contacts the surface of the patient's skin. In such FES devices, the contact with the pad can cause irritation to the patient's skin. For example, many known FES devices include the use of hydro-gel electrodes that can cause skin irritation to the patient over prolonged use.
FES is a means to communicate with the neuromuscular system for producing contraction in muscles or sensory input to the body. FES can be used in neuroprostheses for restoring active function to paralyzed or plegic body limbs in patients suffering disease or trauma to the central nervous system, in neurological conditions such as stroke, spinal cord injury, head injury, cerebral palsy and multiple sclerosis. Surface FES systems use controlled electrical currents through electrodes placed on the surface of the body, in order to trigger contraction from muscles underlying the electrode or to input sensory stimulus. Surface neuroprostheses can coordinate the FES-activation of several muscles of the limb alone, or in coordination with voluntary activation of muscles under natural neurological control. Surface neuroprostheses are in use today for functional activities such as walking, standing, gripping/releasing objects, etc.
Activation of selected muscles of a limb by FES to generate controlled movements has been used, both as a therapeutic modality and for the improvement or restoration of activities of daily living (ADL) or functional restoration. Devices based on surface electrical stimulation which have been developed for activating specific body sites include, for example, the dropfoot system, which activates the ankle joint, modifying hemiplegic gait; hybrid FES-orthosis systems for restoring gait in spinal cord-injured patients, and systems for therapeutic activation and functional restoration of the hand.
In many of the known FES devices, replacement of dried-out pads and/or electrodes can be complex, making it difficult for a patient to perform without assistance. In addition, the location of the pad relative to the electrode is not always well-defined, producing a possible misalignment between the electrode and the motor point of the muscle, which can cause an undesirable overflow of the electrical stimulus. Thus, electrode placement is an important issue for surface neuroprostheses and involves accurately positioning the electrodes over the motor points of the muscles to be activated. Accurate electrode positioning can ensure activation of the correct muscle without overflow to unwanted muscles, sensory tolerance of the stimulation current intensity needed to produce the desired response, and the quality of the muscle contraction.
Thus, there is a need for an electrode and/or electrode kit for use in conjunction with an orthosis that can be easily and accurately attached to and removed from the orthosis by the clinician or by the patient. There is also a need for an electrode that provides patient comfort and reduces or eliminates skin reactions to the electrode.